Polaris Sportsman 90 - Manual (Page 29)

R--13
PRE RIDE CHECK
Make sure the brakes don’t stick. Check the brake levers by squeezing
them toward the handlebar and then letting it go. They should come right back
to where they were before you squeezed. If they go back slowly or stay on, your
brakes are sticking.
If you have used the storage area under the seat, make sure the seat is
locked and in place.
If you have sticky brakes, do not start the engine. You could get hurt if you
ride when you have sticky brakes. Have an adult or your Polaris Dealer fix
the sticky brakes.